I'm new to python and trying to write a python script using the field calculator in ArcMap for a specific field in an attribute table that will replace some of the values in the field but leave the other values as they are within the table.
For example: ""fourth" must be changed to "4th" whereas "Neilston" should remain as it is in the field. The field in the table looks like this:
The python script used in the codeblock looks like this:
def streetNUM(field):
if field == "fourth":
field.replace ("fourth","4th")
elif field == "fifth":
field.replace ("fifth","5th")
else:
return field
And then in the box below the codeblock I have:
streetNUM(!FULLNAME!)
Nothing seems to change and I get an error code saying:
Field is not nullable [FULLNAME]
Any suggestions as to where I may be going wrong with my code?